高功率模組使用液冷式散熱之研究

Abstract

本研究使用水作為工作流體，要來解決電動車高功率模組因為高發熱量和不均勻發熱的問題，本研究提出兩種作法，第一種是使用發泡銅當作散熱器，一共做了三種加熱瓦數分別為2510W、2890W、3300W，我們在冷板上擺放三片尺寸完全相同但孔數率不同的發泡銅並改變其擺放順序，來找出效果最佳的擺放順序，由於在電子散熱中，我們在意的是最高溫度，研究結果顯示擺放順序30-20-10PPI其效果最佳，且不同發泡銅的擺放方式最大可以降低18%的熱阻。第二種是使用一般直通道，一共做了兩種加熱瓦數分別為2890W、3300W，本研究一共實驗四種不同形式的直通道，分別為傳統直通道、四分流直通道、區塊直通道和梯形直通道，比較這四種通道其效果最佳為區塊直通道，研究結果也顯示改變通道形式能降低壓降，但是太少的鰭片面積將會導致散熱效果不佳。將上述兩種形式的散熱冷板與沒有鰭片的平板作比較，可以發現在相同泵浦功之下使用傳統直通道可以降低30%-39%的熱阻，若是使用發泡銅更是能降低44%-62%的熱阻。

In this study, the performance of liquid heat sinks using the copper foams and macrochannel applicable for electrical car for enhanced heat transfer is investigated experimentally. A total of 3 different pore density copper foams are made and arranged in a water-cooled cold plate. Test results indicate that with the presence of copper foam may lead to an appreciable increase in the pressure drop but it also provides a considerable heat transfer augmentation due to its unique dispersion characteristics. By placing high pore density copper foams at the inlet, the water velocity profile becomes uniform so that temperature distribution is better. This is because the high pore density copper foams have high resistance to spread the working fluid evenly. Seven distinctive test sections have been examined. The results reveal that the arrangements which followed by medium and low density pore density foams with high pore density copper foams can facilitate a more uniform temperature distribution of the cold plate. The experimentally measured results show that the thermal resistances of copper foams heat sinks are better than plate heat sinks about 44%-62%. A total of 4 different macrochannel heat sinks are arranged in a water-cooled cold plate, including a general parallel plate design, separated for sectional design, a block arrangement and a trapezoidal macrochannel heat sink. The pressure drop of separated for sectional design, block and a trapezoidal type are lower than the general parallel type. Under the same pumping power, the block type has the lowest thermal resistance which is about 30%-39% lower than plate heat sink.